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[76.88.6.86]) by smtp.googlemail.com with ESMTPSA id d2e1a72fcca58-71944bc9dc5sm4251658b3a.191.2024.09.16.16.05.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Sep 2024 16:05:13 -0700 (PDT) From: Daniel Yang To: viro@zeniv.linux.org.uk, Namjae Jeon , Sungjong Seo , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Daniel Yang , syzbot+e1c69cadec0f1a078e3d@syzkaller.appspotmail.com Subject: [PATCH v3] fs/exfat: resolve memory leak from exfat_create_upcase_table() Date: Mon, 16 Sep 2024 16:05:06 -0700 Message-Id: <20240916230506.232137-1-danielyangkang@gmail.com> X-Mailer: git-send-email 2.39.2 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 If exfat_load_upcase_table reaches end and returns -EINVAL, allocated memory doesn't get freed and while exfat_load_default_upcase_table allocates more memory, leading to a memory leak. Here's link to syzkaller crash report illustrating this issue: https://syzkaller.appspot.com/text?tag=CrashReport&x=1406c201980000 Signed-off-by: Daniel Yang Reported-by: syzbot+e1c69cadec0f1a078e3d@syzkaller.appspotmail.com --- V2 -> V3: free(NULL) is no-op, removed if() check V1 -> V2: Moved the mem free to create_upcase_table fs/exfat/nls.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/exfat/nls.c b/fs/exfat/nls.c index afdf13c34..1ac011088 100644 --- a/fs/exfat/nls.c +++ b/fs/exfat/nls.c @@ -779,8 +779,11 @@ int exfat_create_upcase_table(struct super_block *sb) le32_to_cpu(ep->dentry.upcase.checksum)); brelse(bh); - if (ret && ret != -EIO) + if (ret && ret != -EIO) { + /* free memory from exfat_load_upcase_table call */ + exfat_free_upcase_table(sbi); goto load_default; + } /* load successfully */ return ret;